E. V. Budko

Stability of ascorbic acid in aqueous and aqueous-organic solutions for quantitative determination

The stability of ascorbic acid is studied in dependence on the pH of its aqueous solution. It is shown that itenhances in acidic and weakly alkaline media and upon the addition of acetonitrile. The stabilizing effect of ethanol is considerably lower. Processes occurring in aqueous and aqueous-organic solutions of ascorbic acid are considered and the results obtained are explained. These data are important for the development of analytical procedures and can be used in the chemical and pharmaceutical industries for improving the stability of preparations containing ascorbic acid.

High-performance liquid chromatography in the analysis of multicomponent pharmaceutical preparations

A review of publications for the last 10–12 years on the HPLC analysis of multicomponent pharmaceutical formulations is presented. The peculiarities of the analysis of drug products are discussed, including applied adsorbents, mobile-phase composition, elution mode, derivatization procedure, detectors, and methods for reducing the time of analysis. The use of ion-exchange, ion-pair, and enantioselective HPLC in determining the components of pharmaceutical preparations is considered.

Chromatographic separation of paracetamol, caffeine, and aspirin on an adsorbent with immobilized nitrile groups and the analysis of Askofen P tablets

The chromatographic properties of the pharmaceutical preparations of paracetamol, caffeine, and aspirin are studied on adsorbents with immobilized nitrile groups. The effects of the concentration of acetonitrile and potassium phosphate in the mobile phase and the pH of the mobile phase on the retention of analytes and a possible additive, salicylic acid, are studied. In comparison to a column with a C18 adsorbent used earlier for routine analysis, the chromatograms obtained are characterized by higher separation efficiency, while the proposed separation procedure is more cost-effective and rapid.

Quantitative analysis of Pentalgin N tablets by gradient and isocratic high-performance liquid chromatography

Two procedures were proposed for the quantitative analysis of the drug Pentalgin N with the use of HPLC in gradient and isocratic modes. Analgin (dipyrone), caffeine, naproxen, phenobarbital, codeine, an analgin degradation product, and sodium sulfite (added to the test solution to stabilize analgin) were separated on a column (150 × 3.9 mm) packed with Nova-Pak C18 (4.0 μm) with elution with a 0.00625 M KH2 PO4 solution with an acetonitrile concentration gradient from 10 to 60 vol % in 10 min or on a column (150 × 3.9 mm) packed with Nova-Pak CN HP (4.0 μm) with elution with a 0.0110 M KH2 PO4 solution (pH 5.8) containing 5 vol % acetonitrile. The wavelength of the diode-array detector was 212 nm. Model solutions containing all of the active principles and additives of the tablets were analyzed, and the performance characteristics of both procedures were calculated. Both procedures afford reliable analytical results; however, the isocratic version is technically simpler and more preferable for product control in commercial production.

Decomposition of Analgin in aqueous acetonitrile solutions

The stability of Analgin in aqueous acetonitrile solutions was studied depending on the concentrations of acetonitrile and stabilizer (sodium sulfite) and the pH of the solution. It was shown that the concentration of the organic solvent had the most effect on the decomposition rate. The results obtained can be used to develop procedures for determining Analgin and in pharmacology and medicine to improve the stability of Analgin-containing formulations.

Reaction of ephedrine hydrochloride with sodium crosscarmellose and its account in the analysis of ephedrine-containing preparations

It is shown by HPLC and Fourier-transform IR spectrometry that ephedrine hydrochloride (EH) reacts with an auxiliary pharmaceutical substance, sodium crosscarmellose, in aqueous-organic solutions and in dry mixtures. This process may lead to the underestimation of the results of determining EH in the analysis of preparations containing these components. A probable mechanism of the reaction of EH with sodium cross-carmellose is considered, and possible techniques for eliminating its interfering effect are proposed.

Kinetic-chromatographic determination of 4-methylaminoantipyrine in Pentalgin N and Pentalgin FS tablets

Abstract4-Methylaminoantipyrine (4-MAAP) is the main product of analgin decomposition in aqueous-organic solutions used in the analysis of Pentalgin N and Pentalgin FS tablets. The determination of 4-MAAP in tablets is complicated by the fast decomposition of analgin in the course of sample dissolution. The use of nonaqueous solvents in subsequent HPLC analysis is unreasonable, because the shapes of analyte peaks are deteriorated and the decomposition of analgin is not prevented. A procedure for the kinetic-chromatographic determination of both 4-MAAP in tablets and its amount at the moment of sample dissolution is proposed.

Retention of analgin and anesthesin on sorbents with different polarities: The analysis of bellalgin tablets by high-performance liquid chromatography

The effects of acetonitrile and potassium dihydrogen phosphate concentrations in a mobile phase and the pH of the mobile phase on the retention of analgin (dipyrone) and anesthesin (benzocaine) on Symmetry C18 and Nova-Pak CN HP sorbents with grafted octadecylsilanol and nitrile groups, respectively, were studied. It was found that, under identical conditions, retention on the sorbent with grafted nitrile groups was weaker. A rapid and cost-effective procedure was developed for the determination of analgin and anesthesin in the analysis of Bellalgin tablets.

Analytical methods for studying the stability of pharmaceutical compositions and the compatibility of their components

A review of publications on studying the stability of pharmaceutical preparations and interactions of their components is presented. Volumetric and physical factors activating decomposition processes are considered. Specific features of mixture analysis by optical, chromatographic, and thermoanalytical methods are discussed together with the advantages and disadvantages of methods and possibilities of their combination.

Chromatographic analysis of Passifit multicomponent pharmaceutical syrup

Procedures are developed for the qualitative analysis of a new pharmaceutical preparation, Passifit syrup. The conditions for the separation of the active substances were optimized. Valerian and hop extracts were detected by thin-layer chromatography on Kieselgel 60/Kieselguhr F254 plates. Menthol (the volatile component of peppermint oil), thymol and its isomer carvacrol (the components of thyme extract), and sorbic acid (preserving agent) were identified by gas-liquid chromatography on a capillary column with an OV-101 stationary phase and a flame-ionization detector. Luteolin, thymol, rutin, and sorbic acid were identified by reversed-phase HPLC on a Zorbax SB C18 column in a gradient elution mode with UV detection at 210 and 330 nm. Rutin was not detected among the components of the syrup.